Looks like a great science experiment and engineering challenge but I can't see the practicality of it. 90% efficient is spectacular for inductive charging but far below what can be achieved with plug in. With the costs of electricity involved here 8-9% efficency is large. If you've got to have your car parked for two hours or more then the effort of plugging it in is very minor.

It is only impractical if your only goal is efficiency. If your goal is convenience, then it is very practical. Electric cars (especially from Tesla, BMW, and Daimler) are very expensive, which means they are luxury cars. Being able to just get in your car and drive without fiddling with power cords is an added luxury. I'm guessing that the extra 10% electricity cost isn't an overriding issue for such customers.

Lots of people use inductive chargers for their cell phones and tablets, and it is equally inefficient. I personally don't mind plugging in the cable (for my phone), but I can understand that some people prefer the convenience of just throwing thier phone on the charging pad when they get home.

Let us say "not very practical, YET". I like to remind people that before SpaceX and Tesla, there were many things people said were not possible in the industries. But Elon Musk and co have just done them so effectively that Detroit and others are worried. Time will tell if this can be done in a practical-production scale.

I don't have any doubt about the technical feasibility of this. The technology behind this isn't "rocket science." Practicality is very different than technical feasibility or even production worthiness.

I just didn't see the value will justify the costs. Some of the points made by other posters are good though. If I'm paying $100k for a car then I don't care about an extra 10% on energy and $10k to install an inductive coil in my garage just to save the effort to plug it in every day.

Agreed. That's a huge loss of electricity/money over the lifetime of a car. I think a robotic arm that physically connects the two would be much more practical. No need for precise driving, much less energy losses, and if designed right, would still allow quick disconnects happening as soon as you open the car door.

I'm a bit dubious of the 90% figure. I wonder if you could really get that efficiency in the field. It just seems like it might be better to have an automated system that engages a mechanical connection, perhaps also from underneath the car.

Inductively charging a car in the garage at home (with suitable positioning information) adds a level of convenience but I see serious issues associated with charging elsewhere. Not only will the industry need to standardize on the system used in your car (which you may keep for 8 or more years) but also the neighboring cars will need to park properly so that your car can be precisely parked over the inductive coil. Will drivers have to learn the art of precision parallel parking - or will charging spots be well separated diagonal / perpendicular parking places that are easy to access?

>> If I'm paying $100k for a car then I don't care about an extra 10% on energy and $10k to install an inductive coil in my garage just to save the effort to plug it in every day.

In reality, we are not paying the real value. In economics, they have inelastic and elastic demand. There are things that have value because few can afford them. In you buy a car for $100k because you want to save on gas, that person has a problem with math!